1. Field of the Invention
This inventions relates to surgical instruments and, more particularly, to an instrument for holding a needle to facilitate manipulation of that needle as during suturing.
2. Background Art
There are several different types of needle holders currently available on the market. In open surgical procedures, it is known to hold a needle with an instrument that operates much like a pair of conventional pliers. The user can squeeze a pair of handles with or without a locking mechanism thereon with a force that dictates the gripping force on the needle. This type of instrument has several drawbacks. First of all, it is not suitable for the performance of suturing using laparoscopic techniques, due to its size and the amount of space required to effect operation thereof. Another drawback with this type of device is that if the needle holder is modified to accommodate the small space requirement of laparoscopy, as by making the jaws in the form of an alligator forceps, the amount of mechanical force available with the smaller pivoted jaws may not be sufficient to hold the needle securely and the needle can be easily displaced or dropped by the user. Furthermore, laparoscopic suturing often requires awkward positioning of the user's hand and subsequent transmission of the force applied against the needle along unfavorable lines. This may result in the inadvertent torquing or escape of needle from the instrument. Laparoscopic suturing requires a needle holder with a trapping mechanism that allows the needle to remain stable and securely within the device, regardless of the amount or direction of force applied during a procedure.
One commercially available instrument overcomes the above problems. This device is currently being sold by Cook Urological and is identified as its "Endoscopic Curved Needle Driver". This instrument has a pistol-type grip for actuation and has a needle holding mechanism, as shown in FIGS. 9 and 10 of the present application. The instrument has an outer sleeve with a cut-out therein defining a V-shaped, rearwardly opening seat for a needle. The needle seat is spaced a substantial distance away from the free distal end of the outer sleeve. An inner sleeve, concentric with the outer sleeve, is biased towards the front of the instrument. The inner sleeve has a blocking edge that is angularly disposed with respect to the axis of the inner sleeve and in moving forwardly through the slot in the outer sleeve, captively wedges the needle into the seat defined in the outer sleeve. The bias from the inner sleeve is sufficient by itself to hold the needle securely in an operative position allowing suturing to be performed. This allows the user to concentrate solely on manipulation of the instrument.
The latter device has a number of drawbacks. Most notable of these drawbacks is the location of the needle seat, which is spaced substantially away from the free distal end of the outer sleeve. This arrangement makes it impossible for the user to direct the instrument lengthwise of a needle to effect operative engagement therewith. For example, if a needle were to escape from the instrument, the user would have to reposition the instrument, possibly at a severe angle, to allow the needle to re-enter the cut-out and re-seat.
A further drawback with the latter device is that the gripping force on the needle is dictated by the structure which biases the inner sleeve in a forward direction. In the event that the spring force decreases, as may occur over time, the gripping force on the needle may diminish to the point that the instrument may need to be reconstructed or discarded.
A further disadvantage with the latter device is that it is capable of holding the needle, and particularly a curved needle, in only one orientation. This necessitates the construction of several different models to accommodate left- and right-handed persons as well as limiting the versatility of each such model.
A still further drawback with the latter device is that the needle, in its operative position, is situated a substantial distance behind the free distal end of the instrument. As a result, the portion of the outer sleeve that is forwardly of the position of the needle acts as an obstruction which may block the performance of certain suturing procedures. This leading portion has to be pushed into the tissues or otherwise moved out of the way to place the instrument at an awkward angle, before the sharp point of the needle can be presented at the leading edge of the tissue to be sutured.
A still further problem with the latter device is that the cut-out, through which the needle must be introduced, is small and is positioned on one side of the sleeve, thereby creating a blind spot on the other side. Therefore, the cut-out is not always readily visible to the user during laparoscopic procedures. The user may be required to blindly search for the cut-out and may be required to constantly rotate the needle to locate the needle in the cut-out to seat the needle in its operative position. This complicates the surgical procedure and may undesirably prolong the same as the user continuously releases and re-grips a needle as occurs during the normal suturing process.